1. Field of the Invention
The present invention relates to an improvement in an apparatus, such as a camera, with a parallax correcting function, which is used to correct parallax of a finder for viewing an object through a light path which is different from the photographic light path.
2. Description of the Related Art
In general, a camera, such as a compact camera, which comprises a finder optical system used for viewing an object through a light path which is different from the photographic optical system light path, has a problem that the actual photographic range on the film surface and the range viewed by the photographer using a finder do not exactly match. This phenomenon is called parallax, and various measures have been conventionally proposed to correct this problem.
Such measures include providing a plurality of field of view frames for correcting parallax within the finder field of view to provide an index of parallax to the photographer, moving the finder field of view mask in accordance with a distance to be photographed, and displaying the field of view pattern on a liquid crystal display. In Japanese Examined Patent Publication No. 3-92831, parallax is corrected by using, as the finder optical system, a prism whose apex angle varies in accordance with a distance to be photographed.
In cameras which use a zoom optical system for the photographic lens, a zoom optical system is also commonly used for the finder in order to subject the finder to zooming with the zooming of the photographic lens. In such a case, parallax occurs not only when a distance to be photographed changes, but also when the finder optical system is subjected to zooming. Parallax becomes considerable, the higher the magnification of the zoom ratio. Japanese Examined Patent Publication No. 7-86631 discloses a camera construction in which the magnification change-over optical system is mechanically shifted with changes in the finder magnification (focal length).
In the camera disclosed in the aforementioned Japanese Examined Patent Publication No. 7-86631, parallax produced as the finder magnification changes can be corrected, but parallax produced as the distance to be photographed changes cannot be corrected. None of the conventionally proposed cameras are capable of correcting both the parallax produced with changes in the finder magnification and the parallax produced with changes in distance to the object to be photographed.
In view of the above-described problem, the applicant has disclosed, in Japanese Patent Application No. 8-35774, a camera which not only corrects parallax produced with changes in the finder magnification, but also parallax produced with changes in distance to the object to be photographed, which could not be corrected by the camera in the aforementioned Japanese Examined Patent Publication No. 7-86631. More specifically, the proposed camera is capable of correcting parallax produced between near distance photography and far distance photography.
The camera proposed in Japanese Patent Application No. 8-35774 has the problem of being large and costly, since another drive source needs to be specially provided for parallax correction.